We have come across over the years that log home foundations have failed for  a number of reasons. Drainage around the foundation has undermined and caused the log structure to sink and eventually crack or break. We’ve seen some log structures that have been built directly on the ground or on stacked rocks. These are most of the time much older log structures. The biggest problem is that this is not stable for the bearing load of the log walls and will create uneven floors and rot. What needs to and should be done is the log structure should be raised and a footing/stem wall be poured. This is a slow process since you have to keep in mind that windows, doors, utility’s and attic truss’s can possibly be damaged if not careful.  Within the crawl space concrete pads should be poured, screw jacks placed on the pads and horizontal beams placed against the floor joists. This will add strength to the floor system.  French drains should also be placed around the perimeter to deviate water and keep the crawl space dry.